A few months ago, I think I finally figured out what to use chorus on for great benefit. I was reverse engineering a preset on Lush-101. It sounded great and I wanted to figure out why. The usual way to reverse engineer is to selectively start turning things off, usually starting with effects. I turned off the chorus and the sound became thin and dull. So, the moral of the story seems to be: don't use chorus on something that already sounds good because it can muddy things up. But it can sometimes be used to make a thin, anemic timbre full and deep.